Tight, hypertrophic skin loses elasticity

Introduction It is a mixed manifestation of lupus erythematosus, dermatomyositis or polymyositis, scleroderma rheumatoid arthritis, etc. at the same time or at different times, but it is not certain which disease it is, and there is a high-priced spot type in the blood. The connective tissue disease of fluorescent antinuclear antibody and anti-ribonucleoprotein (n-RNP) antibody is less involved in the kidney, has a better effect on corticosteroids, and has a better prognosis. The disease is more common in women, accounting for 80%, the incidence is more common in the 30s, but children and the elderly can criticize.

Cause

According to a variety of immunological abnormalities, autoimmune diseases, patients with B lymphocyte hyperfunction and T-suppressive lymphocyte function, T cell immune regulation abnormalities, and different from SLE, MCTD patients with normal or increased circulating TA cells, However, feedback inhibition of T lymphocytes is impaired. This dysfunction cannot be corrected by serum thymus factor, or the T-suppressive lymphocytes of patients may be impaired in inhibiting T-helper lymphocytes, or because U1RNP antibodies can pass Fc receptors. Penetrating mononuclear cells, T-inhibitory cells are also defective, and the function of the patient's mononuclear phagocytic system to clear the immune complex Fc receptor is normal.

Anti-dsDNA antibodies are less or negative and anti-nRNP antibodies are increased. Some people think that infections such as viruses produce cell damage and ENA has soluble properties, which are easier to enter into the bloodstream than DNA, promote antibody production and formation of immune complexes, and then sink into each Organs and organs that produce related symptoms.

As for the incidence of kidney in MCTD, Morris and Hamberger have shown that ENA can inhibit the synthesis of immune complexes of DNA and anti-DNA antibodies, thus protecting the kidneys. However, recent studies have found that kidney involvement can be as high as 25%. , suggesting that the RNP immune complex has no protective effect.

an examination

Related inspection

Skin elasticity test blood routine blood biochemistry six tests

1 myositis (severe). 2 lung damage, a. DLco <70%, b. pulmonary hypertension, c. biopsy showed pulmonary vascular proliferation damage. 3 Renault phenomenon or abnormal function of esophageal peristalsis. 4 swollen hands or fingertips hardened. 5 anti-ENA antibody titer 1: 10,000, and anti-U1RNP antibody (10), anti-Sm antibody (a), the diagnosis conditions should meet the four indicators above and exclude anti-Sm antibody (10), but even if clinically consistent In the case of Sharp's diagnosis, some cases were converted into other connective tissue diseases.

Differential diagnosis

1. Systemic lupus erythematosus: sacral erythema, kidney involvement and severity, anti-dsDNA, anti-Sm antibody positive, high LE cell positive rate, rare shrub type wrinkle capillary abnormalities, rare swelling of the hand and fingers Hardening can be distinguished from mixed connective tissue disease.

2. Scleroderma: The skin hardening of this disease is not limited to the face, hands, arms, neck and trunk. The ANA fluorescence karyotype can be seen in addition to spots, and the positive rate of anti-nRNP antibody is low. For low titers, the effect on corticosteroids is also poor and can be identified.

3. Dermatomyositis or polymyositis: Mixed connective tissue disease has several characteristics of lupus erythematosus and scleroderma outside of dermatomyositis, and serum high positive rate and high titer anti-nRNP antibody can be distinguished.

4. Overlap syndrome: The symptoms of such cases need to meet the diagnostic criteria of both diseases at the same time, and there is no high titer anti-nRNP antibody.

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